When you work with electricity, one of the most important tools at your disposal is a voltmeter. This device registers the amount of voltage running through a current at any given point. Voltmeters come in a wide variety of styles, from permanently mounted meters in vehicles to handheld units that electricians use. They can come in a simple analog form or as a digital multimeter that performs many different functions. If you need to test a circuit but do not have a voltmeter, you can build one yourself with some simple objects.

Step 1 - Locate a Metal Coil

To make your own voltmeter, you will need a copper coil that can conduct the electricity. You can find this copper coil in other non-working electrical devices, or you can make your own. It must be thin copper wire that is wrapped tightly around a non-conductive material.

Step 2 - Build a Frame for the Voltmeter

Now you will need to construct the frame of the voltmeter. Start with a small piece of wood, a 6-by-6 inch piece, for the base. Glue two pieces (small 1-inch pieces of lumber), standing up, to the base. They should be about 1/2 inch away from each other.

Step 3 - Attach Plastic Pieces

Cut a small notch in the plastic pieces with the knife to serve as a bearings for the voltmeter. Glue them onto the two pieces of wood that are standing upright.

Step 4 - Glue the Fourth Piece of Wood

Take the fourth piece of small wood and glue it to the side of the two support pieces that are standing upright. This piece should be behind the two and lying across the back of both of them. Glue the copper coil to the center of this final piece of wood.

Step 5 - Build the Meter

Attach a small magnet to the end of a piece of a straw. Use glue to hold the magnet on. Take a sewing needle and push it through the side of the straw until it comes out the other side. It should be near the end where the magnet is located. Place the needle between the two supports resting on the plastic notches. Glue two pieces of metal to the ends of the needle so it will stay in place on the plastic notches.

Step 6 - Test the Voltmeter

Tilt the voltmeter on its side so the magnet swings toward the coil. Place a battery near the coil terminal ends. Use some wire to attach the positive end of the battery to the left side of the coil. Use another wire to connect the negative end of the battery to the right side of the coil. When there is current running through the coil, it will repel the magnet and cause the straw to swing. Once you release the wire from the current, the magnet will swing back to its original zero position.